Method for producing airless tire by additive manufacturing

Abstract

There is provided an additive manufacturing method intended for producing a carcass (24) of an airless tire (1), the additive manufacturing method employing an additive manufacturing machine (20) producing a plurality of layers of structural elements (25) of the carcass (24) in any XY plane perpendicular to the axis of rotation of the carcass (24) by depositing strips of fusible printing material, the tape portion of each structural element (25) has, in any XY plane, a portion that is inserted into the tape portion of each adjacent structural element (25).

Description

Technical Field

[0001] The present invention belongs to the field of methods for manufacturing non-pneumatic tires intended to be assembled to a vehicle.

[0002] The present invention more particularly relates to an additive manufacturing method for manufacturing a non-pneumatic tire by means of a 3D printer by depositing a plastic printable material in successive layers by means of a nozzle. Background Art

[0003] Printers generally include a chamber which forms a housing delimited by walls, inside which there is a platform intended to support the part being printed and a nozzle for supplying the material for manufacturing the part. In order to be able to produce the shape of the part, there is provided a drive system which includes a lifter for vertically moving the platform or the nozzle and translational stages which cross each other and which are intended to horizontally manoeuvre the platform or the nozzle (the nozzle being intended to convey the material for manufacturing the part).

[0004] Document US 6 722 872 particularly describes such a printer.

[0005] A non-pneumatic tire or more generally a tire without an inflation gas is a tire which supports the load by means of structural elements which form the carcass and whose performance is comparable to that of a conventional tire which is subjected to an internal gas (generally air) pressure. A non-pneumatic tire mounted on a hub or a rim is sometimes referred to as a "non-inflatable elastic wheel".

[0006] Hereinafter, the circumferential or longitudinal direction denotes the direction of rotation of the tire, the axial or transverse direction denotes the direction parallel to the axis of rotation of the tire, and the radial direction denotes the direction perpendicular to the axis of rotation of the tire.

[0007] A non-pneumatic tire generally includes, in the radial direction from the inside to the outside:

[0008] - a carcass, which is formed by structural elements and which is intended to cooperate with a rim or a hub,

[0009] - a tread, which is intended to cooperate with the carcass and to transmit the running forces to the carcass, and which is thus worn and ensures the grip of the tire on the ground.

[0010] The carcass includes, in the radial direction from the inside to the outside:

[0011] - a support structure, which is intended to structurally support at least part of the load,

[0012] - a shear band, which is intended to transmit the running forces to the support structure by shear and which at least partly contributes to supporting the load.

[0013] The support structure generally includes, in the radial direction from the inside to the outside:

[0014] - A radial inner membrane, which is intended to be fixed to the rim or hub by a connecting means,

[0015] - A plurality of radial elements or spokes, which are intended to be fixed to the radial inner membrane and the shear band by a connecting means. However, the support structure generally does not define a sealed inner cavity intended to accommodate pressurized gas like a traditional tire. Therefore, a non-pneumatic tire does not need to have a sealed connection to the rim or hub.

[0016] In known embodiments, the shear band includes, from the inside to the outside in the radial direction:

[0017] - A radial intermediate membrane, which is in contact with the support structure,

[0018] - A plurality of shear elements,

[0019] - A radial outer membrane, which is intended to receive the tread and is connected to the radial intermediate membrane by a plurality of shear elements.

[0020] Generally, the tread is fixed to the radial outer membrane of the shear band by a fixing means, which can be, for example, an adhesive or a banding means.

[0021] Therefore, the carcass has a plurality of elements called structural elements, which can include, for example, a radial inner membrane, a plurality of spokes, a radial intermediate membrane, a plurality of shear elements, and a radial outer membrane.

[0022] Methods for manufacturing the carcass of a non-pneumatic tire well-known to those skilled in the art include: first, manufacturing various structural elements independently, and second, assembling the structural elements according to an assembly and precise positioning method. Different methods such as adhesive bonding, riveting, bolting, crimping, or ultrasonic welding can be used to hold the various structural elements in place.

[0023] For example, such methods for assembling non-pneumatic tires are described in documents US20220194129A1, WO2008 / 136099A1, US9908369B2.

[0024] Although such methods can manufacture non-pneumatic tires, their disadvantages are particularly related to the weak adhesion between the various elements constituting such a carcass.

[0025] In addition, the manufacturing quality of such carcasses intended for the production of non-pneumatic tires is not always satisfactory. There are variations in the geometric dimensions related to the manufacturing of each structural element plus variations in the positioning in the assembly method, which potentially have an adverse impact on the overall quality and performance aspects of the non-pneumatic tire.

[0026] In addition, the assembly method is quite complex and requires a large number of interventions to position the various structural elements, which results in high manufacturing costs.

[0027] Other methods for manufacturing a non-pneumatic tire carcass using molding methods for producing different structural elements are also known to those skilled in the art. These methods are described, for example, in document JP 2022034665A.

[0028] These methods for manufacturing structural elements by molding require the manufacture of expensive tools such as molds and cannot generate complex geometries that are sometimes necessary for manufacturing the structural elements of a non-pneumatic tire carcass. SUMMARY OF THE INVENTION

[0029] Accordingly, the present invention aims to overcome the above disadvantages and provide a manufacturing method for simply producing a carcass of a non-pneumatic tire at low cost, which manufacturing method can use a wide range of materials while ensuring excellent reproducibility in manufacturing and ideal adhesion between various structural elements of the non-pneumatic tire carcass.

[0030] The subject of the present invention is an additive manufacturing method for a carcass of a non-pneumatic tire for a vehicle, which uses an additive manufacturing machine including a manufacturing platform and a nozzle, the manufacturing platform being perpendicular to the axis of rotation of the carcass having an axial direction Z, the nozzle being capable of moving along the axial direction Z and capable of moving in any circumferential plane XY perpendicular to the axial direction Z, the additive manufacturing method including the following successive steps:

[0031] (a) Manufacturing a first layer of the carcass extending along the axial direction Z by depositing a printing material via the nozzle on the manufacturing platform, thereby forming, in any order, the following cordons:

[0032] - A radial inner membrane cordon, which is intended for manufacturing the radial inner membrane of the carcass and has a first width,

[0033] - A radial intermediate membrane cordon, which is intended for manufacturing the radial intermediate membrane of the carcass and has a second width,

[0034] - A radial outer membrane cordon, which is intended for manufacturing the radial outer membrane of the carcass and has a third width,

[0035] - A plurality of spoke cordons, which are intended for manufacturing a plurality of spokes connecting the radial inner membrane to the radial intermediate membrane, each of the spoke cordons having a fourth width, each of the spoke cordons having at least one first region that penetrates into the radial inner membrane cordon, the first penetration region having a first arc length and a first maximum thickness along the radial direction, each of the spoke cordons further having at least one second region that penetrates into the radial intermediate membrane cordon, the second penetration region having a second arc length and a second maximum thickness along the radial direction,

[0036] - Multiple shear element strip portions, which are intended for manufacturing multiple shear elements for connecting a radially intermediate film to a radially outer film, each of the shear element strip portions having a fifth width, each of the shear element strip portions having at least one third region that penetrates into the radially intermediate film strip portion, the third penetration region having a third arc length and a third maximum thickness along the radial direction, each of the shear element strip portions further having at least one fourth region that penetrates into the radially outer film strip portion, the fourth penetration region having a fourth arc length and a fourth maximum thickness along the radial direction,

[0037] (b) Generate at least one additional layer according to step (a), and the strip portion of the at least one additional layer is stacked axially along the axial direction Z with the strip portion of the axially adjacent previous layer, wherein the interface between the previous layer and the at least one additional layer is remelted.

[0038] Substantially, the additive manufacturing method according to the present invention enables the carcass of a non-pneumatic tire to be obtained by implementing a single method of depositing the printing material exiting the nozzle in the form of strip portions, without the need to assemble multiple components to form the carcass. Therefore, each structural element of the carcass is composed of axially stacked layers, and each layer is composed of a single strip portion or "single strip portion", and the "single strip portion" can save time and improve the manufacturing quality of the non-pneumatic tire carcass, while improving the mechanical strength of the carcass.

[0039] Therefore, the additive manufacturing method of the present invention can eliminate the process of assembling various structural elements required for manufacturing the carcass of a non-pneumatic tire, thereby saving manufacturing time and improving the production quality of the non-pneumatic tire carcass.

[0040] In addition, the additive manufacturing method according to the present invention does not require tools to manufacture various structural elements, thereby reducing the manufacturing cost of the carcass.

[0041] Since the strip portions of the materials deposited through the nozzle of the additive manufacturing machine penetrate into each other in the connection regions of various structural elements, the mutual adhesion of the various structural elements is improved, so that the carcass can obtain better mechanical strength performance and / or fatigue limit performance.

[0042] Advantageously, the first width, the second width, the third width, the multiple fourth widths, and the multiple fifth widths are equal to each other, so that the time for preparing the carcass model can be reduced and the production time can be saved.

[0043] Advantageously, the first width, the second width, the third width, the multiple fourth widths, and the multiple fifth widths are respectively at least equal to 0.15 mm and at most equal to 4 mm, preferably at least equal to 0.4 mm and at most equal to 2 mm. Such a size range enables the subject article to be manufactured with standard nozzle sizes and existing parameter settings of the additive manufacturing machine.

[0044] Advantageously, the first maximum thickness, the second maximum width, the third maximum thickness, and the fourth maximum thickness are equal to each other, so that the time for preparing the carcass model can be reduced and the production time can be saved.

[0045] Advantageously, the first maximum thickness is at least equal to 2% of the minimum width of the first width and the fourth width and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the first width and the fourth width and at most equal to 10% of the minimum width.

[0046] Again advantageously, the second maximum thickness is at least equal to 2% of the minimum width of the second width and the fourth width and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the second width and the fourth width and at most equal to 10% of the minimum width.

[0047] Advantageously, the third maximum thickness is at least equal to 2% of the minimum width of the second width and the fifth width and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the second width and the fifth width and at most equal to 10% of the minimum width.

[0048] Advantageously, the fourth maximum thickness is at least equal to 2% of the minimum width of the third width and the fifth width and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the third width and the fifth width and at most equal to 10% of the minimum width.

[0049] The intervals defined by the first thickness, the second thickness, the third thickness, and the fourth thickness above can maximize the interpenetration of consecutive layers without adding additional materials that may accumulate and cause manufacturing defects or even machine downtime and deterioration.

[0050] Advantageously, the first arc length, the second arc length, the third arc length, and the fourth arc length are equal to each other, so that the time for preparing the carcass model can be reduced and the production time can be saved.

[0051] Advantageously, the first arc length is at least equal to 3 times the minimum width of the first width and the fourth width and at most equal to 100 times the minimum width, preferably at least equal to 10 times the minimum width of the first width and the fourth width and at most equal to 50 times the minimum width.

[0052] Again advantageously, the second arc length is at least equal to 3 times the minimum width of the second width and the fourth width and at most equal to 100 times the minimum width, preferably at least equal to 10 times the minimum width of the second width and the fourth width and at most equal to 50 times the minimum width.

[0053] Advantageously, the third arc length is at least equal to three times the minimum width of the second width and the fifth width and at most equal to 100 times the minimum width, preferably at least equal to ten times the minimum width of the second width and the fifth width and at most equal to 50 times the minimum width.

[0054] Advantageously, the fourth arc length is at least equal to three times the minimum width of the third width and the fifth width and at most equal to 100 times the minimum width, preferably at least equal to ten times the minimum width of the third width and the fifth width and at most equal to 50 times the minimum width.

[0055] The intervals defined by the first arc length, the second arc length, the third arc length, and the fourth arc length above enable sufficient adhesion between structural elements without increasing the stiffness and mass of the wheel.

[0056] Preferably, the spokes are distributed at a constant pitch in the circumferential direction.

[0057] Again preferably, the shear elements are distributed at a constant pitch in the circumferential direction.

[0058] The constant-spacing distribution of the spokes and the shear elements enables the obtained carcass to have the same mechanical operation (especially under applied radial forces) throughout the circumference of the airless tire.

[0059] Preferably, the printing material is a thermoplastic of the polyaryletherketone (PAEK) type, a thermoplastic of the polyetheretherketone (PEEK) type, an aliphatic polyamide (PA), a polyetherimide (PEI), a polyimide (PI), an ethanolized polyester (PETG), or an elastomeric thermoplastic copolyester (TPC-ET). Examples of polyaryletherketone (PAEK) are products from Victrex TM product AM Examples of elastomeric thermoplastic copolyester (TPC-ET) are products from DuPont TM products

[0060] Advantageously, the printing material has a melting temperature of at least 180 °C and at most 450 °C, enabling sufficient thermal integrity during operation for less demanding applications and good plasticity during the manufacture of the carcass according to the present invention.

[0061] Advantageously, the printing materials of at least two types of the belt portions of the radial inner membrane belt portion, the radial intermediate membrane belt portion, the radial outer membrane belt portion, the spoke belt portion, and the shear element belt portion are different, enabling the specification of stiffness or flexibility for each structural element.

[0062] Other subjects of the present invention are a carcass produced by using the manufacturing method according to the present invention, and an airless tire including such a carcass. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Other objects, features and advantages of the present invention will become more apparent by reading the following description in detail and referring to the accompanying drawings, which are provided by way of non-limiting illustration only, in which:

[0064] - Figure 1 : An overall perspective view of a non-pneumatic tire including a carcass produced by an additive manufacturing method according to the present invention.

[0065] - Figure 2 : An overall view of an additive manufacturing machine for implementing the method according to the present invention.

[0066] - Figure 3 : An overall top view of the first layer deposited on the manufacturing platform of the non-pneumatic tire carcass.

[0067] - Figure 4 : A partial view of an axial section of a non-pneumatic tire produced by the method according to the present invention.

[0068] - Figure 5 : A partial view of a circumferential section of a non-pneumatic tire carcass produced by the method according to the present invention.

[0069] - Figure 6 : A view of a circumferential section of the first interpenetrating region.

[0070] - Figure 7 : A view of a circumferential section of the second interpenetrating region.

[0071] - Figure 8 : A view of a circumferential section of the third and fourth interpenetrating regions. DETAILED DESCRIPTION OF THE INVENTION

[0072] In the following, for the sake of clarity, the horizontal and vertical directions correspond to Figures 1 to 7 the natural orientation. Similarly, the terms "top", "bottom", "lower", "upper" and their variants should be understood with reference to the vertical direction in the figures.

[0073] As Figure 1 can be seen, the non-pneumatic tire 1 includes, radially from the inside to the outside:

[0074] - A carcass 24, which is intended to cooperate with a rim or a hub 4,

[0075] - A tread 2, which is intended to cooperate with the carcass 24.

[0076] The carcass 24 includes, radially from the inside to the outside:

[0077] - A support structure 9, which is intended to cooperate with a rim or a hub 4,

[0078] - Shearing band 3, which is designed to cooperate with the tread 2.

[0079] The support structure 9 includes, in the radial direction from the inside to the outside:

[0080] - A radial inner membrane 7, which is designed to be fixed to the rim or hub 4 by a connection method,

[0081] - A plurality of radial elements or spokes 8, which are designed to connect the radial inner membrane 7 and the shearing band 3.

[0082] The method for connecting the radial inner membrane 7 to the rim or hub 4 can be, for example, bonding, riveting, bolting or banding.

[0083] In a known embodiment, the shearing band 3 includes, in the radial direction from the inside to the outside:

[0084] - A radial intermediate membrane 10, which is in contact with the support structure 9,

[0085] - A plurality of shearing elements 11,

[0086] - A radial outer membrane 5, which is designed to receive the tread 2 and is connected to the radial intermediate membrane 10 by a plurality of shearing elements 11.

[0087] The tread 2 can be fixed to the radial outer membrane 5 of the shearing band 3 by a fixing method, and the fixing method can be, for example, bonding or banding.

[0088] Therefore, the carcass 24 is composed of structural elements 25, and the structural elements 25 include a radial inner membrane 7, spokes 8, a radial intermediate membrane 10, shearing elements 11 and a radial outer membrane 5.

[0089] The subject of the present invention is a method for producing the carcass 24 of a non-pneumatic tire 1 by using an additive manufacturing machine 20.

[0090] Figure 2 Fig. is an overall view of an embodiment of an additive manufacturing machine 20 for performing the method according to the present invention. The additive manufacturing machine 20 includes a nozzle 12, a manufacturing platform 14, a system 22 for horizontally moving in any circumferential plane XY, and a system 23 for vertically moving along the axial direction Z perpendicular to any circumferential plane XY.

[0091] The horizontal moving system 22 and the vertical moving system 23 enable the relative movement of the nozzle 12 with respect to the manufacturing platform 14, so that the nozzle 12 can deposit the molten printing material 21 in the form of a preferably continuous strip 13.

[0092] Any other type of additive manufacturing machine capable of depositing the plastic printable material 21 on the belt portion 13 is suitable, such as a machine that achieves relative movement of the nozzle 12 relative to the manufacturing platform 14 by moving the manufacturing platform 14.

[0093] In the first step of the method according to the invention, the first layer of the carcass 24 extending along the axial direction Z is produced by depositing the printing material 21 on the manufacturing platform 14 via the nozzle 12, thereby forming the belt portions (C1, C2, C3, C4, C5) in any order.

[0094] As Figure 3 and Figure 5 visible in, the nozzle 12 will deposit:

[0095] - The radial inner membrane belt portion C1, which is intended for manufacturing the radial inner membrane 7 of the carcass 24 and has a first width R1,

[0096] - The radial intermediate membrane belt portion C2, which is intended for manufacturing the radial intermediate membrane 10 of the carcass 24 and has a second width R2,

[0097] - The radial outer membrane belt portion C3, which is intended for manufacturing the radial outer membrane 5 of the carcass 24 and has a third width R3,

[0098] - A plurality of spoke belt portions C4, which are intended for manufacturing a plurality of spokes 8 connecting the radial inner membrane 7 to the radial intermediate membrane 10, and each of the spoke belt portions C4 has a fourth width R4,

[0099] - A plurality of shear element belt portions C5, which are intended for manufacturing a plurality of shear elements 11 connecting the radial intermediate membrane 10 to the radial outer membrane 5, and each of the shear element belt portions has a fifth width R5.

[0100] As Figure 6 shown, each of the spoke belt portions C4 has at least one first region Z1 that penetrates into the radial inner membrane belt portion C1, and the penetrating first region Z1 has a first arc length L1 and a first maximum thickness E1 along the radial direction.

[0101] As Figure 7 shown, each of the spoke belt portions C4 also has at least one second region Z2 that penetrates into the radial intermediate membrane belt portion C2, and the penetrating second region Z2 has a second arc length L2 and a second maximum thickness E2 along the radial direction.

[0102] As Figure 8 visible in, each of the shear element belt portions C5 has at least one third region Z3 that penetrates into the radial intermediate membrane belt portion C2, and the penetrating third region Z3 has a third arc length L3 and a third maximum thickness E3 along the radial direction.

[0103] AsFigure 8 As can be seen, each of the belt portions C5 of the cutting elements further has at least one fourth region Z4 that penetrates into the radially outer membrane belt portion C3. The penetrating fourth region Z4 has a fourth arc length L4 and a fourth maximum thickness E4 along the radial direction.

[0104] In the method according to the invention, the nozzle 12 then produces at least one additional layer according to step a, and the belt portions (C1, C2, C3, C4, C5) of the at least one additional layer are stacked along the axial direction Z with the belt portions (C1, C2, C3, C4, C5) of the axially adjacent previous layer, wherein the interface between the previous layer and the at least one additional layer is remelted.

[0105] As Figure 4 As can be seen, repeating step (a) makes it possible to produce a one-piece carcass 24 having a height H along the axial direction Z. The height H of the carcass 24 clearly has to be adapted to the type of the non-pneumatic tire 1 to be produced. In particular, the height H has to be adjusted to the width of the tread 2 of the non-pneumatic tire 1.

[0106] The remelting of the interface between two adjacent layers makes it possible to obtain a very firm bond between the respective layers, so that it is possible to manufacture a one-piece carcass 24 with very high mechanical strength.

[0107] The generation of the penetrating regions Z1, Z2, Z3 and Z4 during the deposition of the printing material 21 makes it possible to ideally bond the spokes 8 to the radially inner membrane 7 and the radially intermediate membrane 10, and also to ideally bond the cutting elements 11 to the radially intermediate membrane 10 and the radially outer membrane 5.

[0108] This ideal bonding between the structural elements 25 of the carcass 24 enables the carcass 24 to obtain very high mechanical strength and very good fatigue strength under working stresses.

[0109] Preferably, during the process of manufacturing the layers of the carcass 24, the nozzle 12 starts depositing the layer of the radially inner membrane belt portion C1 (which is a belt portion defining a closed region) at a starting point different from that of the previous layer, so as to obtain a joint region between two adjacent layers at different horizontal azimuth angles.

[0110] In the same way, the layers of the other belt portions C2, C3 (each of which also defines a closed region) are also preferably deposited with a starting point and an end point of the nozzle 12 different from those of the previous layer, so that it is also possible to obtain a joint region between the start and the end of the belt portion at different horizontal azimuth angles.

[0111] Obtaining joint regions at different horizontal azimuth angles of the belt portions (which define closed regions) for each layer of the carcass 24 makes it possible to improve the mechanical strength of the carcass 24 by preventing the propagation of any cracks in the joint regions.

[0112] In a specific embodiment, as Figure 5 shown, the first width R1, the second width R2, the third width R3, the plurality of fourth widths R4, and the plurality of fifth widths R5 are equal to each other, and are respectively at least equal to 0.15 mm and at most equal to 4 mm, preferably at least equal to 4 mm and at most equal to 2 mm.

[0113] In another embodiment, the strength of each structural element 25 can be optimized by the following method: adjusting the widths R1, R2, R3, R4, and R5 of the structural element 25. Specifically, each structural element 25 of the carcass 24 has different shapes and stresses, and the respective widths R1, R2, R3, R4, and R5 can be determined as appropriately as possible.

[0114] These thickness differences also make it possible to reduce the weight of the carcass 24, save the amount of deposited material, and save manufacturing time.

[0115] Preferably, as Figure 5 visible, the first maximum thickness E1, the second maximum thickness E2, the third maximum thickness E3, and the fourth maximum thickness E4 are equal to each other.

[0116] Again preferably, the first arc length L1, the second arc length L2, the third arc length L3, and the fourth arc length L4 are equal to each other.

[0117] Advantageously, the first maximum thickness E1 is at least equal to 2% of the minimum width of the first width R1 and the fourth width R4 and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the first width R1 and the fourth width R4 and at most equal to 10% of the minimum width.

[0118] Again advantageously, the second maximum thickness E2 is at least equal to 2% of the minimum width of the second width R2 and the fourth width R4 and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the second width R2 and the fourth width R4 and at most equal to 10% of the minimum width.

[0119] Also advantageously, the third maximum thickness E3 is at least equal to 2% of the minimum width of the second width R2 and the fifth width R5 and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the second width R2 and the fifth width R5 and at most equal to 10% of the minimum width.

[0120] Again advantageously, the fourth maximum thickness E4 is at least equal to 2% of the minimum width of the third width R3 and the fifth width R5 and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the third width R3 and the fifth width R5 and at most equal to 10% of the minimum width.

[0121] Advantageously, the first arc length L1 is at least equal to three times the smallest width of the first width R1 and the fourth width R4 and at most equal to 100 times the smallest width, preferably at least equal to ten times the smallest width of the first width R1 and the fourth width R4 and at most equal to 50 times the smallest width.

[0122] Also advantageously, the second arc length L2 is at least equal to three times the smallest width of the second width R2 and the fourth width R4 and at most equal to 100 times the smallest width, preferably at least equal to ten times the smallest width of the second width R2 and the fourth width R4 and at most equal to 50 times the smallest width.

[0123] Again advantageously, the third arc length L3 is at least equal to three times the smallest width of the second width R2 and the fifth width R5 and at most equal to 100 times the smallest width, preferably at least equal to ten times the smallest width of the second width R2 and the fifth width R5 and at most equal to 50 times the smallest width.

[0124] Also advantageously, the fourth arc length L4 is at least equal to three times the smallest width of the third width R3 and the fifth width R5 and at most equal to 100 times the smallest width, preferably at least equal to ten times the smallest width of the third width R3 and the fifth width R5 and at most equal to 50 times the smallest width.

[0125] As Figure 5 As can be seen, in the interpenetration regions Z1, Z2, Z3, Z4, the strip portion of a structural element 25 of the carcass 24 is tangent to the strip portion of an adjacent structural element 25. This tangency enables the structural element 25 to have a geometry suitable for the type of stress to which the carcass 24 is subjected, thereby improving the mechanical strength and fatigue strength of the structural element 25.

[0126] As is well known to those skilled in the art, the width and height of the printed strip portion depend on the geometric dimensions of the outlet cross-section of the nozzle 12 and the setting parameters of the additive manufacturing machine 20.

[0127] Advantageously, the nozzle 12 of the additive manufacturing machine 20 can be changed during the manufacture of the layer of the carcass 24 so that the width of the deposited strip portion is consistent with the respective widths R1, R2, R3, R4, and R5 of the strip portions C1, C2, C3, C4, and C5 of the structural element 25, thereby enabling each layer of the structural element 25 to be produced with a single pass of the nozzle 12.

[0128] Preferably, the spokes 8 and the shear elements 11 are distributed at a constant pitch in the circumferential direction.

[0129] Still in the method according to the invention, the printing material 21 is preferably a thermoplastic of the polyaryletherketone (PAEK) type (e.g., a product from Victrex TM products ), a thermoplastic of the polyetheretherketone (PEEK) type, an aliphatic polyamide (PA), a polyetherimide (PEI), a polyimide (PI), an ethanolized polyester (PETG), or an elastomeric thermoplastic copolyester (TPC-ET) (e.g., a product from DuPont TM products ).

[0130] Advantageously, the printing material 21 has a melting temperature of at least 180°C and at most 450°C.

[0131] Advantageously, the printing materials 21 of at least two types of belt portions among the radial inner belt portion C1, the radial intermediate belt portion C2, the radial outer belt portion C3, the spoke belt portion C4, and the shear element belt portion C5 are different. Thus, since each structural element 25 has different functional requirements (e.g., in terms of stiffness or flexibility), materials with the most suitable technical characteristics can be selected to produce each structural element 25.

[0132] The invention can be summarized as a carcass 24 for a non-pneumatic tire 1, the carcass 24 including, in the radial direction from the inside to the outside:[[]]

[0133] - at least two support structures 9, the first radial inner membrane 7 of the first support structure 9 being intended to be fixed to a rim or a hub 4, and the other radial inner membranes 7 each serving as an interface between each of a plurality of radial elements or spokes 8,[[]]

[0134] - and / or at least two shear belts 3, the last radial outer membrane 5 being intended to receive a tread 2, and the other radial outer membranes 5 each serving as an interface between each of a plurality of shear elements 11.[[]]

[0135] Table 1 below shows the characteristics of an embodiment intended for manufacturing the carcass 24 of the non-pneumatic tire 1:[[]]

[0136] [Table 1]

[0137]

[0138]

[0139] Other subjects of the invention are a carcass 24 produced using the manufacturing method according to the invention, and a non-pneumatic tire 1 including such a carcass 24.

Claims

1. An additive manufacturing method for a carcass (24) of a non-pneumatic tire (1) for a vehicle, which uses an additive manufacturing machine (20) including a manufacturing platform (14) and a nozzle (12), the manufacturing platform (14) being perpendicular to a rotation axis having an axial direction Z of the carcass (24), and the nozzle (12) being capable of moving along the axial direction Z and capable of moving in any circumferential plane XY perpendicular to the axial direction Z. The additive manufacturing method includes the following consecutive steps: (a) Manufacturing a first layer of the carcass (24) extending along the axial direction Z by depositing a printing material (21) via the nozzle (12) on the manufacturing platform (14), thereby forming, in any order, the following belt portions (C1, C2, C3, C4, C5): - A radial inner membrane belt portion (C1), which is intended for manufacturing a radial inner membrane (7) of the carcass (24) and has a first width (R1). - A radial intermediate membrane belt portion (C2), which is intended for manufacturing a radial intermediate membrane (10) of the carcass (24) and has a second width (R2). - A radial outer membrane belt portion (C3), which is intended for manufacturing a radial outer membrane (5) of the carcass (24) and has a third width (R3). - A plurality of spoke belt portions (C4), which are intended for manufacturing a plurality of spokes (8) connecting the radial inner membrane (7) to the radial intermediate membrane (10), each of the spoke belt portions having a fourth width (R4), each of the spoke belt portions (C4) having at least one first region (Z1) inserted into the radial inner membrane belt portion (C1), the first insertion region (Z1) having a first arc length (L1) and a first maximum thickness (E1) along the radial direction, each of the spoke belt portions (C4) further having at least one second region (Z2) inserted into the radial intermediate membrane belt portion (C2), the second insertion region (Z2) having a second arc length (L2) and a second maximum thickness (E2) along the radial direction. - A plurality of shear element belt portions (C5), which are intended for manufacturing a plurality of shear elements (11) connecting the radial intermediate membrane (10) to the radial outer membrane (5), each of the shear element belt portions (C5) having a fifth width (R5), each of the shear element belt portions (C5) having at least one third region (Z3) inserted into the radial intermediate membrane belt portion (C2), the third insertion region (Z3) having a third arc length (L3) and a third maximum thickness (E3) along the radial direction, each of the shear element belt portions (C5) further having at least one fourth region (Z4) inserted into the radial outer membrane belt portion (C3), the fourth insertion region (Z4) having a fourth arc length (L4) and a fourth maximum thickness (E4) along the radial direction. (b) Generating at least one additional layer according to step (a), the belt portions (C1, C2, C3, C4, C5) of the at least one additional layer being stacked along the axial direction Z with the belt portions (C1, C2, C3, C4, C5) of an axially adjacent previous layer, and the interface between the previous layer and the at least one additional layer being remelted.

2. The additive manufacturing method of the carcass (24) according to claim 1, wherein, The first width (R1), the second width (R2), the third width (R3), the plurality of fourth widths (R4) and the plurality of fifth widths (R5) are equal to each other.

3. The additive manufacturing method of the carcass (24) according to any one of claims 1 and 2, wherein, The first width (R1), the second width (R2), the third width (R3), the plurality of fourth widths (R4) and the plurality of fifth widths (R5) are respectively at least equal to 0.15 mm and at most equal to 4 mm, preferably at least equal to 0.4 mm and at most equal to 2 mm.

4. The additive manufacturing method of the carcass (24) according to any one of claims 1 to 3, wherein, The first maximum thickness (E1), the second maximum thickness (E2), the third maximum thickness (E3) and the fourth maximum thickness (E4) are equal to each other.

5. The additive manufacturing method of the carcass (24) according to any one of claims 1 to 4, wherein, The first maximum thickness (E1) is at least equal to 2% of the minimum width of the first width (R1) and the fourth width (R4) and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the first width (R1) and the fourth width (R4) and at most equal to 10% of the minimum width.

6. The additive manufacturing method of the carcass (24) according to any one of claims 1 to 5, wherein, The second maximum thickness (E2) is at least equal to 2% of the minimum width of the second width (R2) and the fourth width (R4) and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the second width (R2) and the fourth width (R4) and at most equal to 10% of the minimum width.

7. An additive manufacturing method of a carcass (24) according to any one of claims 1 to 6, wherein, The third maximum thickness (E3) is at least equal to 2% of the minimum width of the second width (R2) and the fifth width (R5) and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the second width (R2) and the fifth width (R5) and at most equal to 10% of the minimum width.

8. The additive manufacturing method of the carcass (24) according to any one of claims 1 to 7, wherein, The fourth maximum thickness (E4) is at least equal to 2% of the minimum width of the third width (R3) and the fifth width (R5) and at most equal to 20% of the minimum width, preferably at least equal to 5% of the minimum width of the third width (R3) and the fifth width (R5) and at most equal to 10% of the minimum width.

9. An additive manufacturing method of the carcass (24) according to any one of claims 1 to 8, wherein, The first arc length (L1), the second arc length (L2), the third arc length (L3) and the fourth arc length (L4) are equal to each other.

10. The additive manufacturing method of the carcass (24) according to any one of claims 1 to 9, wherein, The first arc length (L1) is at least equal to 3 times the minimum width of the first width (R1) and the fourth width (R4) and at most equal to 100 times the minimum width, preferably at least equal to 10 times the minimum width of the first width (R1) and the fourth width (R4) and at most equal to 50 times the minimum width.

11. An additive manufacturing method of a carcass (24) according to any one of claims 1 to 10, wherein, The second arc length (L2) is at least equal to 3 times the minimum width of the second width (R2) and the fourth width (R4) and at most equal to 100 times the minimum width, preferably at least equal to 10 times the minimum width of the second width (R2) and the fourth width (R4) and at most equal to 50 times the minimum width.

12. An additive manufacturing method for a carcass (24) according to any one of claims 1 to 11, wherein, The third arc length (L3) is at least equal to 3 times the minimum width of the second width (R2) and the fifth width (R5) and at most equal to 100 times the minimum width, preferably at least equal to 10 times the minimum width of the second width (R2) and the fifth width (R5) and at most equal to 50 times the minimum width.

13. The additive manufacturing method of the carcass (24) according to any one of claims 1 to 12, wherein, The fourth arc length (L4) is at least equal to three times the smallest width among the third width (R3) and the fifth width (R5) and at most equal to 100 times the smallest width, preferably at least equal to 10 times the smallest width among the third width (R3) and the fifth width (R5) and at most equal to 50 times the smallest width.

14. The additive manufacturing method of the carcass (24) according to any one of claims 1 to 13, wherein, The spokes (8) are circumferentially distributed at a constant pitch.

15. An additive manufacturing method of a carcass (24) according to any one of claims 1 to 14, wherein, The cutting elements (11) are circumferentially distributed at a constant pitch.

16. The additive manufacturing method of the carcass (24) according to any one of claims 1 to 15, wherein, The printing material (21) is a thermoplastic of the polyaryletherketone (PAEK) type, a thermoplastic of the polyetheretherketone (PEEK) type, an aliphatic polyamide (PA), a polyetherimide (PEI), a polyimide (PI), an ethanolized polyester (PETG), or an elastomeric thermoplastic copolyester (TPC-ET).

17. The additive manufacturing method of the carcass (24) according to claim 16, wherein, The printing material (21) has a melting temperature of at least 180 °C and at most 450 °C.

18. The additive manufacturing method of the carcass (24) according to claim 16, wherein, The printing materials (21) of at least two types of belt parts among the radially inner belt part (C1), the radially intermediate belt part (C2), the radially outer belt part (C3), the spoke belt part (C4), and the cutting element belt part (C5) are different.

19. The carcass (24) of the non-pneumatic tire (1), which is produced by implementing the manufacturing method according to any one of claims 1 to 18.

20. A non-pneumatic tire (1), which includes the carcass (24) according to claim 19.

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